Ketamine hydrochloride xylazine hydrochloride

Coronal slices were prepared from young adult male APP/PS1 mice or WT littermates at an age of six to seven months. Animals were anesthetized using intraperitoneal injection of ketamine hydrochloride/xylazine hydrochloride (Sigma-Aldrich, Taufkirchen, Germany) and then transcardially perfused with ice-cold 0.9% NaCl solution. After opening the cranium, the brains were gently removed and the right hemibrains were postfixed in 4% PFA/0.1 M phosphate-buffered saline (PBS) for 24 h at 4 °C and then cryoprotected in 25% sucrose (AppliChem, Darmstadt, Germany) in PBS. The left hemibrains were quickly placed in ice-cold artificial cerebrospinal fluid (ACSF) solution, anterior cortex, posterior cortex and hippocampus were dissected and all brain areas were snap-frozen for protein analysis. The fixed hemispheres were then cut to 40 µm thick coronal slices using a cryostat (Leica CM 3050, Wetzlar, Germany). Three free-floating sections 240 µm apart from each other (between Bregma levels −2.46 mm and −3.08 mm according to Franklin and Paxinos [43 ], containing the hippocampus and cortex were selected for all histological fluorescent stainings. For imaging experiments, all sections were transferred to slides (Superfrost, Thermo Scientific, Dreieich, Germany), coverslipped with ImmunoMount mounting medium (Thermo Scientific, Dreieich, Germany).